Operators, such as those used for casement windows, typically have a mounting platform, which rotatably includes a gear and a pull arm. The gear meshes with a worm gear on a shaft, often with a handle affixed to the shaft. The pull arm is coupled to the window. Rotating the worm shaft rotates the gear and the pull arm thereby opening and closing the window. In some instances, a second pull arm is used. The second pull arm often engages the first pull arm by means of another gear or pivot arrangement, the two arms ultimately driven by rotating the single worm shaft. A typical operator of this type has a cover and a base, the cover and base trapping a first gear. At least one operator arm with a second gear affixed thereto and a bearing therebetween are pivotally installed between the cover and the base. The cover has a post at each end passing through a hole in the base and is swaged to retain the two components together when assembled.
A high torque applied to the input shaft of the operator imparts a high rotational torque on the gear. The high rotational torque causes the gear teeth to generate a undesirable axial force, in addition to the expected tangential force. The axial force tends to push the gear against the cover and at least one of the operator arms toward the base, thereby tending to separate the gear and operator arm and causing two problems. The first problem is that separation allows the gear teeth to slide away and out of position, thereby reducing the extent of the engagement between the gear teeth with other components. Overtime this separation causes failure of the gear teeth. The second problem is that the separation causes the bearing to have reduced contact with either the cover or the base. The reduced contact, in turn, generates stresses causing deformation failure of the bearing support surfaces of the base and/or the cover. These problems, either alone or in combination, will cause the window operator to become difficult to operate or to completely fail to operate.
For these reasons, there is a need for a window operator assembly which maintains proper alignment and engagement of internal components, particularly meshing gears, to prevent undue stress from inducing inefficient operation or a total failure.